Combination dolly-pallet

ABSTRACT

The dolly-pallet of the present invention includes a load bearing deck that may be alternately supported by the retractable support skid or the wheel elements. Initial displacement of the skid during the retraction process is along an upward substantially vertical path. Once the retractable support skid is retracted such that the dolly-pallet is being supported by the wheel elements, the retractable support skid may be further displaced along an upward substantially arcuate path so as to move it away form the wheel elements, allowing them to swivel if they are so configured. In this way, the center of mass of the load is lowered vertically, thereby reducing stress on the displacement mechanism until the load is supported by the wheel elements.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to dollies and pallets and, in particular, it concerns a combination dolly-pallet.

The prior art is replete with wheeled dollies and pallets with retractable wheels. Wheeled dollies, however, are generally not usable on roller conveyer devices, and pallets generally must be lifted off the ground in order to be moved.

One problem with some pallet designs utilizing retractable wheels is that the wheels are fixed to the displacement mechanism rather than directly to the pallet. Therefore, the stresses of moving the loaded pallet are applied to the displacement mechanism rather than to the solid part of the pallet. Reliable devices require heavy displacement mechanisms. Further, the displacement path of the wheel elements includes some degree of lateral displacement while the wheel elements are supporting the full weight of the pallet and its contents. Here again, the stresses of the load are applied to the displacement mechanism rather than to the solid part of the pallet.

There is therefore a need for a combination dolly-pallet with wheels that are fixedly attached and a retractable contact surface that supports the dolly-pallet while in a non-rolling state, wherein the retractable contact surface is displaced along a substantially vertical path. It would be beneficial if the retractable contact surface were configured as a retractable support skid.

SUMMARY OF THE INVENTION

The present invention is a combination dolly-pallet

According to the teachings of the present invention there is provided, a combination dolly-pallet device comprising: a) a load bearing deck portion; b) a plurality of wheel elements attached in fixed relationship to the load bearing deck portion; c) at least one retractable contact surface mechanically linked to the load bearing deck portion; and d) at least one displacement mechanism associated with the retractable contact surface, the displacement mechanism configured to displace the retractable contact surface along a substantially vertical path between a support state in which at least of portion of the combination dolly-pallet device is supported by the retractable contact surface, and a retracted state in which at least a portion of the combination dolly-pallet device is supported by the plurality of wheel elements.

According to a further teaching of the present invention, there is also provided, a fixed leg portion having an internal volume such that the at least one wheel element and the at least one displacement mechanism are at least partially deployed within the internal volume.

According to a further teaching of the present invention, the at least one wheel element is configured to swivel.

According to a further teaching of the present invention, the displacement mechanism is configured so as to displace the retractable contact surface to a position in which the at least one wheel element is free to swivel.

According to a further teaching of the present invention, the displacement mechanism is configured such that after the retractable contact surface is displaced along the substantially vertical path, the retractable contact surface is further displaced along a substantially arcuate path.

According to a further teaching of the present invention, the at least one retractable contact surface is configured as at least a first pair of retractable contact surfaces and the at least one displacement mechanism is configured as at least a first pair of displacement mechanisms, and the first pair of displacement mechanisms are mechanically linked so as to be substantially simultaneously actuated by a common actuation linkage.

According to a further teaching of the present invention, the first pair of retractable contact surfaces is interconnected so as to form a first retractable contact skid.

According to a further teaching of the present invention, there is also provided, at least a second pair of interconnected retractable contact surfaces and at least a second pair of displacement mechanisms so as to form at least a second retractable contact skid.

There is also provided according to the teachings of the present invention, a method for interchanging a dolly-pallet between a non-rolling pallet state and a rolling dolly state, the method comprising: a) providing a load bearing deck portion; b) providing a plurality of wheel elements attached in fixed relationship to the load bearing deck portion; c) providing at least one retractable contact surface mechanically linked to the load bearing deck portion; d) providing at least one displacement mechanism associated with the retractable contact surface, and e) displacing the retractable contact surface along a substantially vertical path between a support state in which at least of portion of the combination dolly-pallet device is supported by the retractable contact surface, and a retracted state in which at least a portion of the combination dolly-pallet device is supported by the plurality of wheel elements.

According to a further teaching of the present invention, there is also provided, providing a fixed leg portion having an internal volume such that the at least one wheel element and the at least one displacement mechanism are at least partially deployed within the internal volume.

According to a further teaching of the present invention, the at least one wheel element is implemented so as to swivel.

According to a further teaching of the present invention, the displacement mechanism is implemented so as to displace the retractable contact surface to a position in which the at least one wheel element is free to swivel.

According to a further teaching of the present invention, the displacement mechanism is implemented such that after the retractable contact surface is displaced along the substantially vertical path, the retractable contact surface is further displaced along a substantially arcuate path.

According to a further teaching of the present invention, the at least one retractable contact surface is implemented as at least a first pair of retractable contact surfaces and the at least one displacement mechanism is configured as at least a first pair of displacement mechanisms, and the first pair of displacement mechanisms are mechanically linked so as to be substantially simultaneously actuated by a common actuation linkage.

According to a further teaching of the present invention, there is also provided, interconnecting the first pair of retractable contact surfaces is so as to form a first retractable contact skid.

According to a further teaching of the present invention, there is also provided, providing at least a second pair of interconnected retractable contact surfaces and at least a second pair of displacement mechanisms so as to form at least a second retractable contact skid.

There is also provided according to the teachings of the present invention, a combination dolly-pallet device comprising: a) a load bearing deck portion; b) a plurality of wheel elements attached in fixed relationship to the load bearing deck portion; c) at least one retractable contact surface mechanically linked to the load bearing deck portion; and d) at least one displacement mechanism associated with the retractable contact surface, the displacement mechanism configured to perform a two-stage displace of the retractable contact surface such that a first stage of the two-stage displacement is a high force/torque motion and a second stage of the two-stage displacement is a low force/torque motion.

According to a further teaching of the present invention, the first stage of the two-stage displacement is sufficient to displace the at least one retractable contact surface when the at least one retractable contact surface is under load.

According to a further teaching of the present invention, the second stage of the two-stage displacement is sufficient to displace the at least one retractable contact surface away from a region of the plurality of wheels when the at least one retractable contact surface is not under load.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic isometric view of a dolly-pallet constructed and operative according to the teachings of the present invention, shown here being supported by the retractable support skids;

FIG. 2 is a schematic isometric view of the embodiment of FIG. 1, shown here with the retractable support skids retracted vertically;

FIG. 3 is a schematic isometric view of the embodiment of FIG. 1, shown here with the retractable support skids displaced along a substantially arcuate path after having been lifted vertically;

FIG. 4 is an isometric view of a first preferred embodiment of a displacement mechanism constructed and operative according to the teachings of the present invention, this embodiment utilizing eccentric pins for displacing the retractable support skids, here the retractable support skid has been lifted vertically;

FIG. 4A is a detail of FIG. 4;

FIG. 5 is an isometric view of the embodiment of FIG. 4 showing the retractable support skids displace along a substantially arcuate path after having been lifted vertically;

FIG. 6 is a side elevation of a variant of the displacement mechanism of FIG. 4 in which the actuating gear is a worm gear accessible from the top of the load bearing deck;

FIGS. 6A and 6B are side elevations of the variant of FIG. 6 showing the retractable support skid being retracted vertically;

FIG. 7 is an isometric view of a second preferred embodiment of a displacement mechanism constructed and operative according to the teachings of the present invention, this embodiment utilizing levers to displace the retractable support skid, here the retractable support skid has been lifted vertically;

FIG. 7A is a detail of the region B in FIG. 7, the displacement mechanism is shown with the retractable support skids supporting the dolly-pallet;

FIG. 7B is a detail of the region B in FIG. 7, the displacement mechanism is shown with the retractable support skids displaced vertically and the dolly-pallet being supported by the wheel elements;

FIG. 8 is an isometric view of the embodiment of FIG. 7 showing the retractable support skid displaced along a substantially arcuate path after having been lifted vertically;

FIG. 8A is a detail of FIG. 8 for clarity;

FIG. 9 is an isometric view of a third preferred embodiment of a displacement mechanism constructed and operative according to the teachings of the present invention, this embodiment utilizing worm gears and drive screws to displace the retractable support skid;

FIG. 9A is a detail of FIG. 9;

FIGS. 10-12 are isometric views of a fourth preferred embodiment of a displacement mechanism constructed and operative according to the teachings of the present invention, this embodiment utilizing slideable wedges to displace the retractable support skid;

FIG. 13 is an isometric view of a “knockdown” variation of the embodiment of FIG. 7;

FIG. 14 is an isometric view of the embodiment of FIG. 13, after the release button has been displaced and the retractable support skid has been lifted vertically;

FIG. 15 is an isometric view of the displacement mechanism as deployed in FIG. 14;

FIG. 16 is an isometric view of the embodiment of FIG. 13, after the retractable support skid has been displaced along a substantially arcuate path; and

FIG. 17 is an isometric view of the displacement mechanism as deployed in FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a combination dolly-pallet.

The principles and operation of combination dolly-pallet according to the present invention may be better understood with reference to the drawings and the accompanying description.

By way of introduction, FIGS. 1-3 schematically illustrate a number of the principles of the dolly-pallet 2 of the present invention. According to the teachings of the present invention, the load bearing deck 4 may be alternately supported by the retractable support skid 6 or the wheel elements 8. Further, the displacement mechanism of the present invention provides a substantially locked support state when the load bearing deck 4 may be alternately supported by the retractable support skid 6 such that retractable support skid 6 is substantially locked from vertical displacement (as seen in FIGS. 6A, 7A and 9). Initial displacement of the skid during the retraction process is along an upward substantially vertical path. In this way, the center of mass of the load is lowered vertically, thereby reducing stress on the displacement mechanism, until the load is supported by the wheel elements 8. Once the retractable support skid 6 is retracted such that the dolly-pallet is being supported by the wheel elements 8, the retractable support skid 6 may be further displaced along an upward substantially arcuate path to move it away form the wheel elements 8, allowing them to swivel if they are so configured. Therefore, the two-stage displacement motion preferably corresponds to a high force/torque motion sufficient to the retractable support skid 6 when under load, followed by a low force/torque motion for displacing the unloaded retractable support skid 6 from the region of the wheels along the arcuate path.

It will be appreciated that only some of the wheel elements 8 may be configured to swivel. That is, to rotate about a vertical axis such as, but not limited to, a caster. Therefore, only those retractable support skids 6 associated with swivel wheel elements 8 s need be displaced further to allow the swivel wheel elements freedom to swivel. This is illustrated in FIG. 3 where only retractable support skid 6 a is displaced away form the wheel elements 8 s.

It will be understood that directional terms such as “up,” “upward,” “down,” “downward,” “top,” “bottom,” “clockwise,” and “counter-clockwise” are used herein in reference to those directions as they appear in the drawings.

Applying the principles of displacing the retractable support skids 6 first along an upward vertical path and then displacing the retractable support skids 6 further along an upward arcuate path to move it away from the wheel elements 8 may be achieved by any number of displacement mechanisms. Discussed herein are five preferred embodiments offered as examples only. It will be apparent to one of ordinary skill in the art that other displacement mechanisms may be used with equal success. Although the embodiments illustrated herein are directed toward displacement mechanisms and wheel elements that are deployed within an interior volume of a fixed leg portion extending downward from the load bearing deck of the dolly-pallet, this is considered to be a choice of design rather than a limitation, and the principles of the present invention may be applied without such an enclosure.

It should be noted that for ease of understanding, displacement mechanism elements that serve the same or similar function in each of the embodiments herein described are numbered the same even though there may be slight differences in their individual configurations.

Referring now to the drawings, FIG. 4 illustrates a first preferred embodiment of a displacement mechanism 10. In this embodiment, the retractable support skid 6 is retracted and lowered along a substantially vertical path by support struts 12, which are attached to the rotating lifting bars 14 by eccentric attachment shafts 16. The rotating lifting bars 14 are driven by gears 18 that mesh with drive gears 20 deployed on drive shaft 24.

FIGS. 6, 6A and 6B illustrate a variant 40 of the displacement mechanism of FIG. 4. Here, the gears 18 mesh with worm gear 42, which is accessible from the top of the load bearing deck 4. Also seen clearly in FIGS. 6A and 6B is the process by which the retractable support skid 6 is retracted and lowered along a substantially vertical path by support struts 12. The parallel support struts 12 are pivotally attached at one end to the retractable support skid 6 and at the other end to the eccentric attachment shafts 16. As illustrated in FIG. 6A, when the eccentric attachment shafts 16 are located at the bottom of their circular path, the retractable support skid 6 is in contact with the ground surface and supporting the dolly-pallet (as seen in FIG. 1). As rotating lifting bars 14 rotate (here in a counter-clockwise direction) the eccentric attachment shafts 16 retract the retractable support skid 6 along a substantially vertical path bringing the wheel elements 8 into contact with the ground surface and thereby transferring support of the dolly-pallet from the retractable support skid 6 to the wheel elements 8 (as seen in FIG. 2).

As illustrated in FIGS. 4 and 4A, as the eccentric attachment shafts 16 reach the top of their circular path, pins 22 engage the edge of support struts 12, thereby causing the support struts 12 to rotate with the rotating lifting bars 14 as they continue to rotate. This displaces the retractable support skid 6 along a substantially arcuate path up and away from the wheel elements 8, thereby allowing the wheel elements 8 s freedom to swivel (as seen in FIG. 3).

It will be appreciated that the retractable support skid 6 may be brought back into contact with the ground surface and the wheel elements 8 lifted, thereby transferring support of the dolly-pallet from the wheel elements 8 back to the retractable support skid 6 (as seen in FIG. 1) by rotating the rotating lifting bars 14 in a clockwise direction and displacing the retractable support skid 6 first along a downward arcuate path toward the wheel elements 8, and then in a substantially downward vertical path to the ground surface.

A second preferred embodiment of a displacement mechanism 60 is illustrated in FIGS. 7, 7A, 7B, 8 and 8A. In this embodiment, the retractable support skid 6 is retracted and lowered along a substantially vertical path by support struts 12, which are attached to levers 62 that extend from the rotating lifting bars 14. The rotating lifting bars 14 are driven by gears 18, which in this embodiment may be driven, by either the drive gears 20 deployed on drive shaft 22 of FIG. 4, or the worm gear 42 of FIG. 6.

FIG. 7A illustrates the position of the levers 62 when the retractable support skid 6 is in contact with the ground surface and supporting the dolly-pallet (as seen in FIG. 1). As rotating lifting bars 14 rotate (here again in a counter-clockwise direction) the levers 62 retract the retractable support skid 6 along a substantially vertical path bringing the wheel elements 8 into contact with the ground surface and thereby transferring support of the dolly-pallet from the retractable support skid 6 to the wheel elements 8 (as seen in FIG. 2).

When the lifting projection 64 of the lever 62 engages the edge of support struts 12 (FIG. 7B), the support struts 12 begin to rotate with the rotating lifting bars 14 as they continue to rotate. This displaces the retractable support skid 6 along a substantially arcuate path up and away from the wheel elements 8 (FIG. 8), thereby allowing the wheel elements 8 s freedom to swivel (as seen in FIG. 3).

An optional feature of the displacement mechanism of the present invention, illustrated here in this embodiment of a displacement mechanism, is the resilient snap-lock arrangement 66 associated with the pivotal interconnection of the support struts 12 and the lever 62. In a first snap-locking position, as seen in FIG. 7A, the resilient snap-lock arrangement 66 helps maintain positional alignment between the support struts 12 and the lever 62 when the skid 6 is supporting the dolly-pallet and during the displacement along the substantially vertical path. In a second snap-locking position, as seen in FIG. 7B, the resilient snap-lock arrangement 66 helps maintain positional alignment between the support struts 12 and the lever 62 during displacement of the skid 6 along the substantially arcuate path.

It will be appreciated that the retractable support skid 6 may be brought back into contact with the ground surface and the wheel elements 8 lifted, thereby transferring support of the dolly-pallet from the wheel elements 8 back to the retractable support skid 6 (as seen in FIG. 1) by rotating the rotating lifting bars 14 in a clockwise direction and displacing the retractable support skid 6 along a downward arcuate path toward the wheel elements 8, and then in a substantially downward vertical path to the ground surface.

A manually operated “knockdown” variation of the second preferred embodiment of a displacement mechanism 260 is illustrated in FIGS. 13-17. In this variation, the retractable support skid 6 is retracted and lowered along a substantially vertical path by support struts 12, which are pivotally attached to levers 62 that extend from the rotating lifting bars 14. The rotating lifting bars 14. In this variation, the retractable support skid 6 is initial retracted from a position of supporting the dolly-pallet (as seen in FIGS. 1 and 13) by “knocking” release button 262, which is mechanically linked to at least on of the rotating lifting bars 14, with a tool such as, but not limited to, a hammer, thereby freeing the displacement mechanism 260 from a locked position. This action also causes the release button to move laterally, causing rotation of rotating lifting bars 14, which may be mechanically linked by gears such as is illustrated in FIG. 5, thereby raising the retractable support skid 6 along a substantially vertical path bringing the wheel elements 8 into contact with the ground surface and thereby transferring support of the dolly-pallet from the retractable support skid 6 to the wheel elements 8 (as seen in FIGS. 2, 14 and 15).

Displacement of the retractable support skid 6 along a substantially arcuate path up and away from the wheel elements 8, thereby allowing the wheel elements 8 freedom to swivel (as seen in FIGS. 3, 16 and 17) is accomplished by rotating the lifting lever 264, here, in a counter-clockwise direction, thereby rotating the rotating lifting bars 14. As lifting projection 64 of the lever 62 engages the edge of support struts 12 (FIG. 17), the support struts 12 begin to rotate with the rotating lifting bars 14.

It will be appreciated that the retractable support skid 6 may be brought back into contact with the ground surface and the wheel elements 8 lifted, thereby transferring support of the dolly-pallet from the wheel elements 8 back to the retractable support skid 6 (as seen in FIGS. 1 and 13), by rotating the lifting lever 264, and therefore, the rotating lifting bars 14 in a clockwise direction and displacing the retractable support skid 6 along a downward arcuate path toward the wheel elements 8, and then in a substantially downward vertical path to the ground surface. This will also bring the release button 262 back into its original position and the displacement mechanism 260 to a locked position, as illustrated in FIG. 13.

It should be noted that FIGS. 15 and 17 illustrate two lifting levers 264 configured on opposite ends of one of the lifting bars 14. This is not intended as a limitation of the present invention, rather it is an example of one possible configuration within the scope of the present invention. It will be understood that a single lifting lever 264 would provide similar results.

A third preferred embodiment of a displacement mechanism 80 is illustrated in FIGS. 9 and 9A. In this embodiment, the retractable support skid 6 is retracted and lowered along a substantially vertical path by support struts 12, which are attached to drive screws 82 that extend from drive gears 84, which are internally treaded such that drive screws 82 are raised and lowered by turning drive gears 84. The drive gears 84 are driven by worm gears 86 configured on drive shaft 88.

As illustrated in FIGS. 9 and 9A the retractable support skid 6 is retracted along a substantially vertical path from contact with the ground surface and supporting the dolly-pallet (as seen in FIG. 1) by rotating drive shaft 88 in a counter-clockwise direction. As the retractable support skid 6 retracts, the wheel elements 8 are brought into contact with the ground surface, thereby transferring support of the dolly-pallet from the retractable support skid 6 to the wheel elements 8 (as seen in FIG. 2). Since support struts 12 are pivotally attached to drive screws 82, the retractable support skid 6 may be displaced along a substantially arcuate path up and away from the wheel elements 8 (FIG. 8), thereby allowing the wheel elements 8 freedom to swivel (as seen in FIG. 3). This may be done manually or by any other suitable drive mechanism (not shown).

It will be appreciated that the retractable support skid 6 may be brought back into contact with the ground surface and the wheel elements 8 lifted, thereby transferring support of the dolly-pallet from the wheel elements 8 back to the retractable support skid 6 (as seen in FIG. 1) by rotating drive shaft 88 in a clockwise direction and displacing the retractable support skid 6 along a substantially downward vertical path to the ground surface.

It should be noted that load bearing deck 4 may be configured such that the drive elements, such as the drive shaft 24, rotating lifting bars 14, and the associated gears, of these first three embodiments of displacement mechanisms of the present invention may be deployed within the structure of the load bearing deck 4 itself. Alternatively, these drive elements may be attached to the underside of the load bearing deck 4.

Illustrated in FIGS. 10-12 is a fourth embodiment 100 of a displacement mechanism by which the retractable support skid 6 is retracted and lowered along a substantially vertical path. In this embodiment, the retractable support skid 6 is upwardly biased toward the legs 102 that extend downwardly from the load beard deck 4 of the dolly-pallet. As seen in FIGS. 11 and 12, as wedges 104 are displace laterally, the retractable support skid 6 is drawn upward along a substantially vertical path toward the bottom surfaces of legs 102, thereby bringing the wheel elements 8 into contact with the ground surface and transferring support of the dolly-pallet from the retractable support skid 6 to the wheel elements 8.

It will be appreciated that the retractable support skid 6 may be brought back into contact with the ground surface and the wheel elements 8 lifted, thereby transferring support of the dolly-pallet from the wheel elements 8 back to the retractable support skid 6 (as seen in FIG. 1) by laterally displacing the wedges 104 back into the region between legs 102 and retractable support skid 6, thereby displacing the retractable support skid 6 along a substantially downward vertical path to the ground surface.

It should be noted that although the embodiments described herein make reference to the retractable support skid 6 as the contact surface when the dolly-pallet of the present invention is deployed in a non-rolling state, this is not intended as a limitation and a dolly-pallet configured with individual retractable contact surfaces associated with each leg is within the scope of the present invention. Further, it will be understood that directions of rotation referred to in the illustrations herein are by way of example only and that actual direction of rotation is considered to be a design consideration. Further, although the displacement mechanisms described herein are directed toward paired displacement mechanisms that are mechanically linked so as to be substantially simultaneously actuated by a common actuation linkage, this need not always be the case and individual actuation of each of the displacement mechanisms is within the scope of the present invention.

It will be appreciated that the displacement mechanism of the present invention may by driven manually or by a drive system, which may be in the form of an onboard drive system, or as a drive system accessory unit. Additionally, an onboard drive system may be activated via a control panel on the dolly-pallet, or remotely via a remote control system.

It will be appreciated that the above descriptions are intended only to serve as examples and that many other embodiments are possible within the spirit and the scope of the present invention. 

1. A combination dolly-pallet device comprising: (a) a load bearing deck portion; (b) a plurality of wheel elements attached in fixed relationship to said load bearing deck portion; (c) at least one retractable contact surface mechanically linked to said load bearing deck portion; and (d) at least one displacement mechanism associated with said retractable contact surface, said displacement mechanism configured to displace said retractable contact surface along a substantially vertical path between a support state in which at least of portion of the combination dolly-pallet device is supported by said retractable contact surface, and a retracted state in which at least a portion of the combination dolly-pallet device is supported by said plurality of wheel elements.
 2. The combination dolly-pallet device of claim 1, further including a fixed leg portion having an internal volume such that said at least one wheel element and said at least one displacement mechanism are at least partially deployed within said internal volume.
 3. The combination dolly-pallet device of claim 1, wherein said at least one wheel element is configured to swivel.
 4. The combination dolly-pallet device of claim 3, wherein said displacement mechanism is configured so as to displace said retractable contact surface to a position in which said at least one wheel element is free to swivel.
 5. The combination dolly-pallet device of claim 4, wherein said displacement mechanism is configured such that after said retractable contact surface is displaced along said substantially vertical path, said retractable contact surface is further displaced along a substantially arcuate path.
 6. The combination dolly-pallet device of claim 1, wherein said at least one retractable contact surface is configured as at least a first pair of retractable contact surfaces and said at least one displacement mechanism is configured as at least a first pair of displacement mechanisms, and said first pair of displacement mechanisms are mechanically linked so as to be substantially simultaneously actuated by a common actuation linkage.
 7. The combination dolly-pallet device of claim 6, wherein said first pair of retractable contact surfaces is interconnected so as to form a first retractable contact skid.
 8. The combination dolly-pallet device of claim 7, further including at least a second pair of interconnected retractable contact surfaces and at least a second pair of displacement mechanisms so as to form at least a second retractable contact skid.
 9. A method for interchanging a dolly-pallet between a non-rolling pallet state and a rolling dolly state, the method comprising: (a) providing a load bearing deck portion; (b) providing a plurality of wheel elements attached in fixed relationship to said load bearing deck portion; (c) providing at least one retractable contact surface mechanically linked to said load bearing deck portion; (d) providing at least one displacement mechanism associated with said retractable contact surface, and (e) displacing said retractable contact surface along a substantially vertical path between a support state in which at least of portion of the combination dolly-pallet device is supported by said retractable contact surface, and a retracted state in which at least a portion of the combination dolly-pallet device is supported by said plurality of wheel elements.
 10. The method of claim 9, further including providing a fixed leg portion having an internal volume such that said at least one wheel element and said at least one displacement mechanism are at least partially deployed within said internal volume.
 11. The method of claim 9, wherein said at least one wheel element is implemented so as to swivel.
 12. The method of claim 11, wherein said displacement mechanism is implemented so as to displace said retractable contact surface to a position in which said at least one wheel element is free to swivel.
 13. The method of claim 12, wherein said displacement mechanism is implemented such that after said retractable contact surface is displaced along said substantially vertical path, said retractable contact surface is further displaced along a substantially arcuate path.
 14. The method of claim 9, wherein said at least one retractable contact surface is implemented as at least a first pair of retractable contact surfaces and said at least one displacement mechanism is configured as at least a first pair of displacement mechanisms, and said first pair of displacement mechanisms are mechanically linked so as to be substantially simultaneously actuated by a common actuation linkage.
 15. The method of claim 14, further including interconnecting said first pair of retractable contact surfaces is so as to form a first retractable contact skid.
 16. The method of claim 15, further including providing at least a second pair of interconnected retractable contact surfaces and at least a second pair of displacement mechanisms so as to form at least a second retractable contact skid.
 17. A combination dolly-pallet device comprising: (a) a load bearing deck portion; (b) a plurality of wheel elements attached in fixed relationship to said load bearing deck portion; (c) at least one retractable contact surface mechanically linked to said load bearing deck portion; and (d) at least one displacement mechanism associated with said retractable contact surface, said displacement mechanism configured to perform a two-stage displace of said retractable contact surface such that a first stage of said two-stage displacement is a high force/torque motion and a second stage of said two-stage displacement is a low force/torque motion.
 18. The combination dolly-pallet device of claim 17, wherein said first stage of said two-stage displacement is sufficient to displace said at least one retractable contact surface when said at least one retractable contact surface is under load.
 19. The combination dolly-pallet device of claim 17, wherein said second stage of said two-stage displacement is sufficient to displace said at least one retractable contact surface away from a region of said plurality of wheels when said at least one retractable contact surface is not under load. 